> > There is also a PRAGMA user_version (see > http://www.sqlite.org/pragma.html#pragma_schema_version) which will let you > store a number in the database header so you can keep track of what version > of the "user schema" you have implemented in the database. Initially, when > the database is created empty, the value is zero. > > pragma user_version; > > returns a single row with a single value which is the version, and the > command, > > pragma user_version=n; > > lets you change it to n. Perhaps you can use this as a flag to tell yourself > that you are working with an uninitialized database (value is 0), that > another process is updating the database schema (change it to -1), or that it > is at some internal revision number known to your program (it has a value > > 0) such that you do not need to change the schema or initialize it. >
This is actually very helpful! This soultion avoids unnecessary transaction after database open. I can use *double checked locking* and start transaction only if necessary. _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
